Diapers each having a bodily fluid absorbent core containing fluid absorbent fibers and superabsorbent polymer particles are known. For example, JP 3208289 B (PTL 1) discloses a diaper having a longitudinal direction, a transverse direction and a thickness direction and including a core sandwiched between a liquid-pervious sheet and a liquid-impervious sheet. The core in this diaper is formed with slits extending therethrough in the thickness direction from a surface thereof facing the wearer's skin to a surface thereof facing away from the wearer's skin. These slits extend in the longitudinal direction.
In this diaper, bodily fluids such as urine flow along the slits and consequently the dispersion of bodily fluids in the longitudinal direction is accelerated.